Resource reservation and call admission control are important facilities to provide in any Internet Protocol (IP) telephony, video conferencing, or Internet multimedia application. Without such facilities, the applications can fail in the presence of Quality of Service (QoS) problems.
The solution to these problems usually involves explicit reservation/admission control signaling by endpoints of the media sessions, through a signaling protocol like Resource Reservation Protocol (RSVP) or the emerging Next Steps In Signaling (NSIS) protocol.
Unfortunately, not all endpoints support these protocols. In order to ameliorate the crippling effects of not having bandwidth reservation or admission control in these cases, Media Transfer Points (MTPs) and admission control proxies have been developed which act on behalf of endpoints lacking the necessary QoS signaling protocols.
These band-aids help, but have a number of disadvantages, chief among them being decreased robustness because there is now a stateful intermediary in the media path between the endpoints. Another disadvantage is higher resource usage because the media traffic no longer flows on the optimal path between the endpoints, and because extra processing is needed to perform the media transfer point functions. In addition, the MTP can easily become a “hot spot” and create QoS problems where they would otherwise not exist.
The present invention addresses this and other problems associated with the prior art.